By Craig Day, The News On 6

TULSA, OK -- Demolition crews are busy tearing down an old bridge leading to downtown Tulsa.

It's the Boulder Bridge, going across the railroad tracks on the north edge of downtown.

The bridge was built eight decades ago and has just become too unsafe to keep open.

Construction on the Boulder Bridge near Tulsa Union Station began in 1929. Now, the bridge is coming down.

"We're just starting getting moving on it," said Duane Schrum, project superintendent.

Duane Schrum with Becco Construction says the years have taken a toll.

"This is more than scary, it's very dangerous. So we're watching our moves very carefully on it," said Schrum.

The Boulder Bridge was once the main avenue leading people into downtown, but because of deterioration, it was closed to vehicle traffic in the late 1990s and later even to foot traffic.

Now its condition is so bad, it needs to be demolished.

"Once we get past that fence line, that's railroad property there, that's when we'll have to start lifting all of our sections away," said Schrum.

The bridge stretches just south of the Brady Theatre to First Street on the north side.

Technically it's a 90 day project, but demolition crews have to work very carefully so they don't damage the railroad lines underneath the old bridge.

Throughout the day, dozens of Burlington Northern Santa Fe trains travel under the bridge.

Any problems caused by demolition work could back up the company's rail shipping.

"Moving on this line, if you interfere for even part of a day would be very expensive," said Schrum.

Demolition crews will reinforce the concrete above the tracks with steel beams and put in chain link netting to keep any concrete from falling below.

Schrum says with those challenges, and the history, this project is one of the most interesting demolition jobs he has had in 30 years of doing bridge work.

It's a job that is expected to be finished by September.

The demolition cost is $2 million.

The ramps leading to the bridge won't be demolished. Instead, they'll remain in place just in case the city decides at some point in the future to build a new bridge.